US4700933A - Shock absorbing apparatus for an engine - Google Patents

Abstract

A casing accommodating a liquid is divided by a partitioning member into two sections. The partitioning member is secured to either an engine or vehicle body,and the walls of the two sections facing the partitioning member are secured to the enging or vehicle body, to which the partitioning member is not secured. The partitioning member is provided with an orifice mechanism which can vary the state of communication between the two sections. When the engine is going to roll, the orifice mechanism is controlled to restrict the communication between the two sections to increase the damping force, whereby the rolling of the engine is prevented.

Description

This application is a continuation of application Ser. No. 587,523, filed on Mar. 8, 1984, and now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a shock absorbing apparatus for suppressing the rolling of an automobile engine.

Recently, automatic transmission vehicles have become prevalent. In a vehicle of this type, torques, generated by the power device, differ in an idling or steady drive state and an automatic gear changing state of the automatic transmission. In the idling of steady drive state, a high-frequency and small-magnitude signal is generated, so that a low torque is generated from the power device. However, in the automatic gear changing state, a low-frequency and large-magnitude signal is generated, so that a high torque is generated.

In a vehicle generating different torques, shock absorbing members, as shown in FIG. 1, having a nonlinear spring characteristic are conventionally disposed between the engine and vehicle body, so as to decrease transmission of the torque (vibration) to the body frame and provide a comfortable drive. The shock absorbing member has an inner cylinder a and an outer cylinder b, as shown in FIG. 2. A rubber plate c is disposed to couple the inner cylinder a and the outer cylinder b. The inner cylinder a is fixed on the engine, and the outer cylinder b is fixed on the body frame, so that the rubber plate c absorbs the shock. However, in a large engine which generates a large torque, the vibration or shock cannot be absorbed by only the rubber plate c. When an automatic gear change occurs, shock occurs. In order to absorb such a shock, as shown in FIG. 3, liquid chambers f and g are formed by upper and lower mount rubber members d and e. An orifice h is formed between the liquid chambers f and g. A portion i is fixed on the body frame and a portion j is mounted on the engine. The shock is absorbed by utilizing a damping force generated when the liquid passes through the orifice h. When vibration having a large magnitude occurs, the damping force occurs by an action between the liquid and the orifice h. However, when a small shock or displacement occurs, the liquid does not pass through the orifice h due to the resistance of the orifice h. Therefore, a spring constant is increased, and a transfer force of the shock is increased, resulting in inconvenience.

SUMMARY OF THE INVENTION

An object of the invention relates to provide a shock absorbing apparatus for an engine, which can control the rolling of the engine by varying the damping force according to the magnitude of the reaction against the engine torque.

According to the invention, there is provided a shock absorbing apparatus for an engine comprising a casing accommodating a liquid, a partitioning member secured to either the engine or a vehicle body and dividing the interior of the casing into two sections, mounting means for securing the walls of the two sections facing the partitioning member to either the engine or vehicle body, to which the partitioning member is not secured, orifice means provided on the partitioning member, for varying the state of communication between the two sections, driving means for driving the orifice means, and control means for operating the driving means by detecting that the engine is going to roll.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing a characteristic of a prior art shock absorbing member;

FIG. 2 is a sectional view showing the construction of a prior art shock absorbing member;

FIG. 3 is a sectional view showing a prior art shock absorber of a liquid sealed type;

FIG. 4 is a perspective view showing an embodiment of the shock absorbing apparatus according to the invention;

FIG. 5 is a plan view showing an embodiment of the shock absorbing apparatus according to the invention;

FIG. 6 is a sectional view showing an embodiment of the shock absorbing apparatus according to the invention;

FIG. 7 is a block diagram showing a control circuit for controlling an embodiment of the shock absorbing apparatus according to the invention;

FIG. 8 is a sectional view showing the relation between the orifice and rotary spool in an embodiment of the invention;

FIGS. 9A to 9C are sectional views taken along the line IX--IX in FIG. 8;

FIG. 10 is a graph showing the relation between the transfer force and displacmenet;

FIGS. 11A and 11B are sectional views showing another embodiment of the rotary spool;

FIG. 12 is a sectional view showing another embodiment of the shock absorbing apparatus according to the invention;

FIG. 13 is a plan view showing a further embodiment of the shock absorbing apparatus according to the invention;

FIG. 14A is a plan view showing the rotary valve of FIG. 13;

FIG. 14B is a sectional view taken along the line VI--VI in FIG. 14A; and

FIG. 15 is a graph showing a spring characteristic representing the load on the flexing chamber shown in FIG. 12 and displacement thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 5 shows a state wherein apower device 2 is mounted on a body frame 1. In FIG. 5, thepower device 2 comprises anengine 3 and an automatic transmission 5. Theengine 3 is supported by first and secondshock absorbing apparatuses 7 and 8, anengine mount 6 and atransmission mount 9.

The first and secondshock absorbing apparatuses 7 and 8 have the same construction and are exemplified by one of them with reference to FIGS. 6 to 10. Referring to FIG. 6,reference numeral 10 denotes a casing mounted on the body frame 1. Thecasing 10 is partitioned by apartition plate 11 into an upperliquid chamber 12 and a lowerliquid chamber 13. Liquid 14 is stored in the upper and lowerliquid chambers 12 and 13. Theliquid 14 is sealed between an elastic body, such as arubber member 15, in the upperliquid chamber 12 and adiaphragm 16 in the lowerliquid chamber 13. A rubber stopper 17 is integrally formed with therubber member 15 so as to oppose aceiling portion 18 of thecasing 10. The rubber stopper 17 controls the upward displacement of therubber member 15. Apin 19 extends upward from therubber member 15. Thepin 19 extends through a throughhole 20 formed in theceiling portion 18 of thecasing 10 and is fixed on thepower device 2. Acover 21 is mounted on the distal end portion of thepin 19. Arubber stopper 22 is adhered to the lower surface of thecover 21 to oppose theceiling portion 18 and to control the displacement of thecover 21.

Anorifice 23 comprising an elongated hole is formed in thepartition plate 11 along the direction corresponding to the thickness of thepartition plate 11, so as to cause the upperliquid chamber 12 to communicate with the lowerliquid chamber 13. Theorifice 23 has a crank-like sectional shape, as shown in FIGS. 8 and 9A to 9C. Abearing hole 24 is formed in a bent portion of theorifice 23 along the longitudinal direction of theplate 11. Arotary spool 25 is rotatably inserted in thebearing hole 24. Avalve portion 26 is formed in the shaft of therotary spool 25 to open/close theorifice 23. Thevalve portion 26 is constituted by an L-shapedlarge channel 27 and asmall channel 28 communicating therewith. Openings of the large andsmall channels 27 and 28 are formed on the outer surface of the shaft of therotary spool 25 at anguar intervals of 90 degrees, so as to selectively oppose theorifice 23. Theorifice 23 is controlled by thevalve portion 26 to be in one of the closed, partially opened, and fully opened states. One of the ends of therotary spool 25 extends outward from the corresponding end of thepartition plate 11 and is connected to a drive source such as arotary solenoid 29. Therotary solenoid 29 is electrically connected tosensors 33 through acontrol circuit 32 having asolenoid drive circuit 30 and alogic controller 31. These sensors detect whether or not there is the possibility of a torque reaction and a torque reaction force, if any. Thecontrol circuit 32 controls therotary solenoid 29 in accordance with the magnitude of the detection signal (torque reaction force), so that the opening of theorifice 23 of thepartition plate 11 is controlled.

While the engine is idling or rotating at high speed, or while the vehicle is traveling at constant speed, a large torque will not be generated. In this case, therotary solenoid 29 cannot function. Therotary spool 25 is therefore held in the initial state as shown in FIG. 9A, and theorifice 23 communicates with thelarge channel 27. Therefore, vibrations transmitted from thepower device 2 to thepin 19 are absorbed by therubber member 15. When therubber member 15 is deformed downward, the liquid 14 in the upperliquid chamber 12 is guided into thelower liquid chamber 13 through theorifice 23. However, when therubber member 15 is deformed upward, the liquid 14 in thelower chamber 13 flows into the upperliquid chamber 12 through theorifice 23. Therefore, the vibrations acting on thepin 19, are not absorbed when the liquid 14 flows through theorifice 23. As a result, the vibrations are not transmitted to the body frame 1 through thecasing 10.

When a shock (low-frequency and large-magnitude vibration) occurs (i.e., when an automatic gear change is made by the automatic transmission 5), a large reaction force against a large torque is generated. The large reaction force is detected by thesensors 33. Thesensors 33 supply detection signals to thecontrol circuit 32. Thecontrol circuit 32 controls therotary solenoid 29 to rotate thespool 25, so that theorifice 23 causes the upper and lowerliquid chambers 12 and 13 to communicate with each other through thesmall channel 28, as shown in FIG. 9B. Therefore, the vibration, transmitted from thepower device 2 to thepin 19, is transmited to therubber member 15. Therubber member 15 is greatly deformed so that the liquid 14 in the upperliquid chamber 12 flows through thesmall channel 28.

Vibration energy, to be transmitted to transferred from thepower device 2 to the body frame 1, can be absorbed by an absorbancy A of therubber member 15, and a damping force B near theorifice 23, as shown in FIG. 10. As a result, the rollings of thepower device 2 are decreased.

In the embodiment described above, the crank-like orifice 23 is fomred in thepartition plate 11. The L-shapedlarge channel 27 and thesmall channel 28 communicating therewith constitute thevalve portion 26 formed in therotary spool 25. However, the present invention is not limited to the above construction. For example, as shown in FIGS. 11A and 11B, awide channel 35 and anarrow channel 36 which are perpendicular to each other can be formed in the shaft of arotary spool 34. In this case, therotary spool 34 can be rotated through 90 degrees to change the opening of anorifice 37.

With the embodiment described above, the damping force is varied according to the magnitude of the torque of thepower device 2, so that it it possible to reliably present the rolling of thepower device 2 with respect to the frame body to prevent the striking of thepower device 2 against the walls of the engine room and other components. When there is no change in the reaction against the engine torque, theshock absorbing apparatuses 7 and 8 are not operated. In this case, the vibrations of thepower device 2, which is supported by therubber engine mount 6 andtransmission mount 9, are absorbed by thesemounts 6 and 9 and are not transmitted to the vehicle body to ensure high comfortability.

Another embodiment of the invention will now be described with reference to FIGS. 12 through 15. The first andsecond shock absorbers 7 and 8 have the same construction, so only one of them will be described in detail with reference to FIGS. 12 through 15. FIG. 12 is an elevational sectional view of ashock absorber 7 or 8. Referring to the figure, the shock absorber comprises a partitioning disc 41 which divides the interior of the shock absorber into two sections, i.e., upper andlower oil chambers 42 and 43. The partitioning disc 41 is secured to the vehicle chassis 1 (FIG. 5). Mounting screws 44 and 45 are mounted in the walls of the upper andlower oil chambers 42 and 43 facing the partitioning disc 41. They are secured to anarm member 10 extending from theengine body 3. The walls of the upper andlower oil chambers 42, 43, in which the stems of the mountingscrews 44 and 45 are mounted, also define upper andlower flexing chambers 46 and 47, respectively. Theupper oil chamber 42 is defined between the partitioning disc 41 andupper flexing chamber 46, and the lower oil chamber 43 is defined between the partitioning disc 41 and lower flexing chamber 47. The partitioning disc 41 has a diametrical bore 48 in which arotary valve 50 is received. The bore 48 consists of alarge diameter section 49 and asmall diameter section 52. Therotary valve 50 has a large diameter portion with a pointed end which is received in thelarge diameter section 49 of the bore 48. Asmall diameter portion 53 of therotary valve 50 slidably penetrates thesamll diameter section 52 of the bore 48. Thelarge diameter portion 53 of therotary valve 50 is formed with anelongated communication hole 54 having a large opening area and extending in the diametrical direction of the partitioning disc 41. The free end of thesmall diameter portion 53 of therotary valve 50 is coupled to asolenoid 55. Therotary valve 50 can be rotated by 90° about its axis by thesolenoid 55. The left end of the bore 48 is sealed by acap 56 provided with an O-ring 57. The partitioning disc 41 has a large hole which is adapted to register with thecommunication hole 54 of therotary valve 50. It also has a small hole 58.Orifice elbows 60 and 61, each having anorifice 59 of a constant sectional area and a constant length, are screwed in the upper and lower ends of the hole 58. The walls of the upper andlower flexing chambers 46 and 47 are provided on the side opposite therespective stopper plates 62 and 63. These walls haverubber protuberances 64. The rubber protuberances 64 on each flexing chamber wall consist of opposite-end rubber protuberances 61-1 having a relatively large height. Three intermediate rubber protuberances 64-2 having a relatively small height are provided at a uniform interval between the opposite-end rubber protuberances 64-1.

Therotary valve 50,solenoid 55, hole 58 andorifice elbows 60 and 61 constitute the orifice mechanism.

The operation of the embodiment of the invention having the above embodiment will now be described. When the vehicle is running at a constant speed, the engine does not roll. Without any rolling, thecommunication hole 54 in therotary valve 50 is vertical, that is, the upper andlower oil chambers 42 and 43 communicate with each other via thecommunication hole 54 in synchronization with the hole in the partitioning disc 41 which has a relatively large area. In this situation, vibrations of theengine body 3 in the vertical direction, are lightly damped through the mountingscrews 44 and 45, the upper andlower flexing chambers 46 and 47, and the upper andlower oil chambers 42 and 43 before being transmitted to the vehicle chassis 1. When the amplitude of the vertical vibration of theengine body 3 is gradually increased, the rubber protuberances 64-1 first strike and are then compressed bystopper plates 62 and 63. With a further increase of the engine body vibration amplitude, the rubber protuberances 64-2 are compressed. FIG. 15 shows the displacement of the upper andlower flexing chambers 46 and 47. The slope of the curve shown increases progressively. It will be seen that a great increase of the load on the upper andlower flexing chambers 46 and 247 can be absorbed with only a comparatively small amount of displacement.

When the accelerator pedal is being depressed at a rate in excess of a predetermined rate to increase the engine throttle valve aperture, theengine body 3 tends to roll due to the reaction against its torque. When the accelerator pedal depression rate exceeds a predetermined rate, thesolenoid 55 is energized to cause therotary valve 50 to rotate 90°. As a result, communication between the upper andlower oil chambers 42 and 43 by therotary valve 50 is blocked. That is, the upper andlower oil chambers 42 and 43 can only communicate via theorifice 59. In this state, the rolling of theengine body 3 is greatly damped. When the amplitude of the rolling is large, therubber protuberances 64 will help dampen the rolling.

The rolling of theengine body 3 is damped several seconds after it has been started. Accordingly, therotary valve 50 is rotated 90° to the initial position several seconds afterwards. The upper andlower oil chambers 42 and 43 can thus again communicate with each other via thecommunication hole 54 of therotary valve 50. Now, vibrations of theengine body 3 are lightly damped by theshock absorbers 7 and 8 before being transmitted to the vehicle chassis 1.

With the shock absorbers as described above, in the absence of the rolling of theengine body 3, the vibrations thereof in the vertical direction are substantially absorbed by the elastic deformation of theengine mount 6, thetransmission mount 9, the upper andlower flexing chambers 46 and 47, and therubber protuberances 64 so that they are barely transmitted to the vehicle chassis 1. On the other hand, any rolling of theengine body 3 is heavily damped by the resistance offered to the fluid in the fluid path of theorifice 59, thus preventing theengine body 3 from striking other vehicle components in the engine room or the vehicle chassis. In addition, pitching of the vehicle body due to the rolling of theengine body 3 can be prevented. Further, since the displacement of theengine body 3 is minimized, the displacement of piping extending from theengine body 3, such as the exhaust pipe, the cooling water duct, and the fuel duct, can also be minimized which is advantageous from the standpoint of effectively utilizing engine room space.

While in the above embodiment oforifice elbows 60 and 61 are provided, it is also possible to construct arotary valve 50 which is also provided with an orifice corresponding to theorifice 59 so that it can block the communication between the upper andlower oil chambers 42 and 43 via thecommunication hole 54 while maintaining the communication with the orifice when engine body rolling causes therotary valve 50 to rotate.

The provision of theorifice elbows 60 and 61 on the partitioning disc 41, however, facilitates the selection of the diameter and length of the orifice, and permits the desired orifice characteristics to be readily obtained while permitting machining expenditures to be reduced.

Further, thecap 56 may be dispensed with and instead, the left and of therotary valve 50 in FIG. 12 may be sealed to the bore 48 with an O-ring. However, with the arrangement of the above embodiment, in which the bore 48 is sealed with thecap 56 and therotary valve 50 has a conically pointed end facing thecap 56, therotary valve 50 may be reduced in size and weight to facilitate its positioning and to ensure its light and smooth movement.

Claims (7)

What is claimed is:

1. An engine shock absorbing apparatus comprising:

a casing containing a liquid;

a partitioning member having an opening therein along its length fastened to said casing and to one of either an engine or an automotive body, thus dividing the inside of said casing into two chambers; said opening extending along a majority of said partitioning member length;

elastic walls provided on a wall section of both chambers for varying the capacity of said chambers by elastic deformation of said elastic wall;

a mounting member which is fixed to the other side of an engine or an automotive body and so supported on the elastic wall of one of said both liquid chambers as to be changed in position relative to said partitioning member;

an elastic stopper which is fitted to one side of either said mounting member or partitioning member outside of said liquid chambers, and is so designed as to contact the other side of said mounting member or partitioning member when said elastic wall is displaced beyond a predetermined extent;

a variable orifice device which is inserted into said partitioning member so as to rotate around the axis of said partitioning member separating said both liquid chambers from each other, is provided with a communication passage for effecting the communication between both liquid chambers, and is designed to vary the manner in which both liquid chambers communicate with each other in accordance with the angle of rotation of said orifice device; said communication passage having an oblate cross section whose axis is parallel to the axis of said variable orifice device and whose length is coextensive with said opening whereby free communication is allowed between said chambers when said communication passage and said opening are aligned;

rotary drive means which is set outside of said casing, and controls the angle at which said rotary valve is turned, thereby adjusting the opened extent of said variable orifice device;

roll-detecting means for detecting the rolling tendency of the engine; and

a control circuit which is electrically connected to said rotary drive means and roll detecting means and sends forth a control signal to said rotary drive means in accordance with the contents of a signal delivered from said roll-detecting means.

2. The engine shock absorbing apparatus according to claim 1, wherein said roll-detecting means is intended to detect whether the accelerator is depressed or released at a higher speed than predetermined; and, when said acceleration is depressed or released at a higher speed than predetermined value, sends forth a control signal to said rotary drive means in order to reduce the opened state of said variable orifice device in a predetermined period.

3. The engine shock absorbing apparatus according to claim 1, wherein said rotary valve is represented by a rotary spool valve, which is provided with said communication passage and an orifice having a smaller cross-sectional area than said communication passage, and is further so designed as to let said communication passage and orifice to selectively communicate with said both liquid chambers.

4. The engine shock absorbing apparatus according to claim 1, wherein said variable orifice device further comprises a fixed orifice formed in said partitioning member so as to effect the constant communication between both liquid chambers with a smaller cross-sectional area than said communication passage; and said rotary valve is so designed as to prevent both liquid chambers from communicating with each other by said communication passage.

5. An engine shock absorbing apparatus according to claim 1, wherein an end of an insertion hole formed in said partitioning member for the insertion of said rotary valve is sealed liquid tight by a cap and a projection which abuts against said cap is formed on said rotary valve.

6. An engine shock absorbing apparatus according to claim 1, wherein said elastic wall faces said partitioning member, and said elastic stopper is an elastic projection provided such that it abuts against said mounting member from the displacement of said elastic wall above a specified amount and is formed integrally with said elastic wall on the outside surface of said elastic wall and is supported by said casing.

7. An engine shock absorbing apparatus according to claim 6, wherein said elastic projection comprises a plurality of projections having different heights.

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